This invention relates generally to accessories for water craft and more particularly concerns devices for signaling the absence of a drain plug from a boat drain when the boat is in a launch condition.
In my U.S. Pat. Nos. 5,162,793 and 5,182,556, drain plug absence indicators are disclosed which employ a stopper which is directly plugged into the boat drain (including any tube used to finish the drain) and a Hall effect switch or magnetic reed switch which is part of a control circuit contained in a housing which is mounted on the boat independently of the stopper. A pivoting latching mechanism on the stopper has a magnet which automatically operatively aligns with the Hall effect switch when the stopper is locked into the boat drain. While these devices work effectively, they do have some shortcomings.
Consistent proper operation requires that the control circuit housing be mounted precisely in a position in which the magnet will be operatively aligned with the Hall effect switch when the stopper is locked in the drain hole. Accuracy in mounting is complicated because the housing is independently mounted on the boat and radially spaced from the drain. Consequently, the location of the housing must be either be precisely measured and marked and the housing accurately held in place, a potential hit-or-miss operation, or the separate stopper and housing simultaneously held in place during the mounting process, typically a two person procedure. Even if the housing is correctly located, since the Hall effect switch is radially displaced in relation to the drain the stopper must be correctly angularly oriented in the drain on every use in order to operatively align the magnet. Furthermore, since the plug is independent of both the housing and the drain, the plug may easily be lost.
It is, therefore, an object of this invention to provide a device for signaling the absence of a drain plug which is self-aligning during the mounting process. Another object of this invention is to provide a device for signaling the absence of a drain plug which is properly aligned regardless of the angular orientation of the stopper in the drain. A further object of this invention is to provide a device for signaling the absence of a drain plug in which the Hall effect switch is not radially displaced from the drain. Yet another object of this invention is to provide a device for signaling the absence of a drain plug in which the plug is not detached from the device. It is also an object of this invention to provide a device for signaling the absence of a drain plug which can be installed by one person.